Conventional evaporative emissions (EVAP) control systems include a vapor canister and vapor transport lines. The vapor canister traps fuel vapor that evaporates from liquid fuel (e.g., gasoline) stored in a fuel tank of the vehicle. Engine vacuum is utilized to deliver the fuel vapor from the vapor canister to the engine through the vapor transport lines and into intake ports of the engine. When an engine is off (e.g., during engine cold starts), however, there is no engine vacuum. The specific composition or concentration of the fuel vapor is also unknown. Accordingly, while such EVAP control systems work for their intended purpose, there remains a need for improvement in the relevant art.